Operators and service providers of mobile and cellular telephone services face tremendous challenges in growing their revenue streams in the face of increasing competition and pricing pressures. Roaming users/subscribers/devices, referred to as roamers, remain an attractive source of revenue for operators, and contribute heavily to the bottom-line because of the additional surcharges placed on roaming calls by many operators. In some cases roamers contribute as much as 40% of the total revenues, while in most cases roamers contribute approximately 8% to 20% of the total revenues. It is thus extremely important to be able to control and influence the roaming network choices that roamers have, in order to maximize the benefits and profits both to the operator as well as the subscriber.
A particularly attractive segment of the roaming market is users who roam frequently between two or more networks in two or more countries and have a need for a local number in each country. A local number in each country in which a user roams both enables local callers in the visited country to call the roamers under cheaper local telephone rates without worrying about international IDD calls, and presents a multi-national appearance. Such international roamers typically buy local pre-paid subscriptions to local cellular telephone services in visited countries. Apart from having to change the SIM card in the cellular telephone or handset every time a roamer uses the local cellular services in a visited country, this also results in erosion of the operator's roaming revenues in the roamer's home country (home operator).
A typical method of supporting two different cellular telephone numbers for use in different countries has service providers using Dual IMSI SIM cards that contain an IMSI/MSISDN entry for each of the partnering operators or service providers. When in a first or home calling area, the home IMSI is selected manually or automatically. When in a partner country outside of the home country or calling area, the partner IMSI is selected manually or automatically. The dual IMSI approach requires use of a SIM having multiple SMSCs and multiple authentication keys (Ki), among other things, thereby resulting in a number of logistical problems. The dual IMSI approach also requires a new type of SIM card, one that includes an STK application. This new SIM card causes the HPMN to extend existing or create new SIM agreements with SIM manufacturers, further increasing costs and complicating the logistics process. In addition, each time the location of the device hosting the SIM card changes, the STK must determine whether it is in a network that requires another home IMSI; this typically results in a significant drain of battery power in the host mobile handset.
Consequently, there is a need for operators in one country (home) to join forces with operators in another country (visited country) in order to offer a local MSISDN in the visited country on the same SIM card, thereby creating a monetarily beneficial relationship to both operators and the roaming user.